1. Field of the Invention
The present invention relates to a liquid crystal display, a liquid crystal projector, and a rear projection apparatus for displaying images and characters using liquid crystals, and in particular, to a projection type of liquid crystal display, liquid crystal projector, and rear projection apparatus.
2. Description of the Related Art
In the multimedia era of nowadays, there has been an increasing demand for an apparatus for communication with picture data. Among other things, a liquid crystal display attracts public attention because it is thinner and less power-consuming and has already developed into a key industry comparable to the semiconductor industry. As a liquid crystal display gets larger in screen size, a production equipment therefore becomes expensive and a liquid crystal display is required to satisfy electrically severe characteristics to drive a larger screen. For this reason, attention has been called to a projection type of liquid crystal display in which a small liquid crystal display panel is prepared and a picture displayed thereon is optically enlarged to be displayed. This is because reduction in screen size enables improving characteristics and reducing cost at the same time, as is the case with a scaling law in which as a semiconductor becomes finer, performances and cost are improved. The liquid crystal display panel is typically connected to an external system with a wire bonding or an anisotropic conductive film.
The point different from a general semiconductor circuit in connection is that the liquid crystal display panel takes electric potential on a light transmitting substrate such as an opposing glass substrate. Japanese Patent Application Laid-Open No. H05-72545 describes a method of taking electric potential wherein an electrode of a glass or resin substrate is directly connected to a flexible printed board by Ag paste in a liquid crystal display panel using a light transmission substrate such as glass or resin substrate. Japanese Patent Application Laid-Open Nos. 2001-249345 and 2002-006339 describe another method wherein electrodes are connected to wirings on the silicon substrate side by conductive material. FIG. 11 is a cross section illustrated in Japanese Patent Application Laid-Open No. 2002-006339. As illustrated in FIG. 11, a first substrate 202 is provided with a common wiring 203 and external connection terminal 204 and a second substrate 212 is provided with an opposite electrode 211. Liquid crystal 215 is sealed between the first and the second substrate 202 and 212. An external connection area 233 and a conductive connection portion 232 such as Ag paste are also illustrated in the figure.